This invention is directed to an improved process for preparing polyarylates and the products produced by said process.
Polyarylates are polyesters derived from a dihydric phenol, particularly 2,2-bis(4-hydroxyphenyl)-propane also identified as Bisphenol-A, and an aromatic dicarboxylic acid, particularly mixtures of terephthalic and isophthalic acids. These polyarylates are high temperature, high performance thermoplastic polymers with a good combination of thermal and mechanical properties. They also have good processability which allows them to be molded into a variety of articles.
Many processes have been described in the literature for the preparation of polyarylates. One such process is th diacetate process. In the diacetate process, a dihydric phenol is converted to its diester derivative, which is then reacted with an aromatic dicarboxylic acid(s), to form the polyarylate.
The polyarylate produced by such processes has been described as being blended with a wide variety of thermoplastic polymers to enhance one or more properties of the polyarylate. Generally, the polyarylate is blended with the thermoplastic polymer in powder or granular form in an extruder and extruded into strands, the strands chopped into pellets and the pellets molded into the desired article.